The present invention relates to a device and method for co-applying two or more liquid components from separate containers via separate liquid channels or tubes having separate outlets. In preferred embodiments the present device and method are useful for co-applying fibrin sealant components with a gas to form a spray.
U.S. Pat. No. 4,359,049 to Redl discloses a double barrel syringe for applying a tissue adhesive such as fibrin glue or fibrin sealant to a human or animal in need thereof. The fibrin sealant described comprises predominantly two major components, a fibrinogen-containing component and a thrombin-containing component, each in liquid form upon use. Essentially, the thrombin and fibrinogen, when mixed, provide that the peptide chains of the fibrinogen are cleaved and conditions are provided so that the resulting fibrin polymerizes into a clot which is useful for sealing fluid and air leaks, in haemostasis and to connect tissue. To avoid premature clot formation double-barrelled applicators are employed which, of course, keep the two components separate until application to a patient is required. The ""049 patent discloses that pistons within the two cartridges, each containing one component, can be commonly actuated to dispense fluid simultaneously from each.
Other prior art patents describe various mixing heads for mixing two or more components used in these and other surgical sealants. For example, U.S. Pat. No. 5,116,315 assigned to Hemaldics describes a head where the liquid conducts leading from the component cartridge enter a mixing chamber fashioned so as to provide a swirling of the components before they exit a common exit channel. Adequate mixing of the components is desired so as to form a uniform fibrin sealant. Inefficient mixing results in the coadministration of fibrinogen and thrombin which may only result in a small yield of actual sealant. A difficulty with fibrin sealant applicators can be the premature formation of the clot within the device, especially those devices where the components are mixed within a mixing head and/or those devices wherein the components exit through a common channel. After the first spray of sealant is complete, a clot may block the exit channels rendering the applicator useless and greatly reducing the surgeon""s flexibility in carrying out the sealant part of the surgical procedure.
U.S. Pat. No. 4,631,055 to Immuno includes a gas conveying channel for blowing a gas through the needle or mixing head during discharge of the components. However, an even, uniform distribution of the materials over the anatomical area of interest is still not achieved. Indeed, a significant amount of the components are wasted.
EP-PS No. 592,242 to Edwardson et al. discloses the first completely autologous fibrin sealant. It provides for the coadministration of a fibrin monomer solution with a buffer solution conducive to polymerisation of the fibrin monomer prepared in less than 30 minutes from a single source of blood (preferably that of the patient to receive the sealant). This break-through technology provides a fixed amount of fibrin monomer solution from a sample of about 140 to 160 ml of blood. Uniform and efficient mixing is even more important in order to benefit from this safe, efficient, autologous sealant product and therefore new devices and methods for applying two or more components to form a surgical sealant would be useful addition to the art.
PCT Application WO 96/17618 discloses a device and a method of applying components of a fibrin sealant. The device comprises a source of a gas and a reservoir for each component wherein the gas source and component reservoirs can be actuated by common means. Each of the reservoirs and gas source are separately in fluid communication with a spray head having a center aperture at its outlet end and annular apertures, arranged concentric with and radially outward from the centre aperture whereby the gas and each of said components are discharged through separate apertures. Preferably, the gas is discharged through the centre aperture and the fibrin sealant forming components are discharged separately through each of the annular apertures.
In accordance with the present invention there is disclosed a method and device for utilizing a gas to co-apply two or more liquid components with enhanced uniformity of mixing of the components resulting in a more homogeneous mixture of the components and a minimal amount of unutilized components. The present device comprises a nozzle head having outlets out of which the liquid components and gas are dispensed and where the outlets are arranged in a straight line with the gas outlet at one end of that line. Also disclosed is a device and method for applying two or more liquid components, e.g., components which form a fibrin sealant, wherein the sources of said components, and preferably the source of a gas to be used, are in fluid communication with an applicator and are remote from that applicator.
In the present method, the flow rates of the components and gas are selected such that the two liquid components are drawn or sucked into the gas being expelled from the nozzle head as they exit their respective outlets of the nozzle head.
In this manner the two or more components are mixed outside the nozzle before they are sucked into the gas jet since the component exiting the outlet farthest from the gas outlet sucked across the outlet nearer to the gas outlet. The components are further mixed in the gas jet and the mixture and gas form a spray. In addition, the outlets are relatively small with the result that a relatively small amount of the components is exposed to the surroundings when the expelling is stopped. Furthermore, the clogging tendency in the outlets is substantially eliminated since there is no mixing of components in the nozzle head. Also the amount of the components remaining in said outlets after the application procedure is almost negligible. The latter factor is of vital importance in connection with a mixture of an autologous fibrin monomer solution and a buffer solution where the amount of fibrin monomer solution is relatively limited and accordingly must be utilized to an optimum.
When the components are discharged at mutually differing volume flows, it is according to the invention particularly advantageous to discharge the component with the lowest volume flow through the outlet accommodated farthest away from the gas jet. In this manner it is ensured that the component being discharged with the lowest volume flow is mixed with the component being discharged with the highest volume flow before said components enter the gas jet in the mixed state.
The expelling of the components through the nozzle head may according to the invention be carried out by means of an expelling means, which is activated by means of an electronic control unit, and the expelling of the gas may be carried out by means of a pump also activated by means of the electronic control unit, said electronic unit in turn being activated by means of a signaller controlled by the user handling the nozzle head. As a result, the expelling of the components and the gas can be carried out in a homogeneous manner at substantially constant volume flows.
In connection with a method using syringes with their respective expelling piston as containers for the components, the interruption of the expelling means through the control unit may according to the invention imply that the control unit activates said expelling means to retract the pistons of the syringes a short distance with the result that the components are retracted a short distance from the outlets of the nozzle. As a result, the risk of the two components coming into contact with one another and consequently the risk of a clogging of the nozzle outlets have been considerably reduced.
The invention relates furthermore to a device for applying a mixture of two liquid components kept in their respective containers, where said components are fed to a nozzle head through their respective liquid-transferring means, said nozzle head comprising a separate outlet channel for each component as well as a separate outlet channel for a gas fed through a gas-transferring means from a gas source, and where said device comprises an expelling means simultaneously activating the containers containing their respective component. The device according to the invention is characterised in that the component outlets and the gas outlet in the nozzle head are aligned along a substantially rectilinear line, the gas outlet being accommodated at one end of the line of outlets. Such a nozzle head is relatively easy to manufacture by way of any convenient means, e.g., injection moulding, and furthermore it ensures an efficient, good mixture of the components.
According to the invention the nozzle head may be supported by an elongated handle, and the component and gas-transferring means may be substantially resilient tubings which extend from said handle to a remote accommodation of the expelling means with the containers and the gas source, respectively. The resulting handling of the nozzle head is relatively easy and can be carried out without interference by the presence of the expelling means and the gas source.
Furthermore, the handle may according to the invention be associated with a push-button for actuation of the expelling means and the feeding of gas through a differential pressure-adjusting device. As a result, the component source containers, e.g., the pistons in the syringe cartridges, can be actuated to supply the gas and components without the presence of electricity adjacent the nozzle head and the associated handle.
When the containers used for the components are syringes with their respective piston for expelling the component in question, the expelling means may according to the invention comprise a holder for the securing of the syringes, and an electrically driven elevator means for a simultaneous actuation of the pistons of the syringes with the result that a particularly accurate and constant volume flow set in advance is obtained through each outlet in the nozzle upon such actuation.
Finally, it is according to the invention particularly preferred that the expelling means and the gas source in form of a gas pump are combined as a separate unit together with an electrically driven control unit, said control unit being adapted to control the expelling means and the gas pump at a signal from the user of the nozzle head.